Characteristics of space mini passive hydrogen maser in Shanghai astronomical observatory

Shanghai Astronomical Observatory is developing space mini passive hydrogen maser for future application in satellite navigation system. Study on key technologies, including miniatured cavity-bulb assembly, absorption pump and magnetic state selection system, have been carried out. Weight of physical package is controlled within 10kg and atomic signal is up to 2dB. Miniatured electronic package weight of 5Kg is developed while keeping system framework as conventional time-separated control method. Engineering model weighting 14.5Kg has been developed. Frequency stability of 1.2×10
^-12
t
^-1/2
(1s ≤ t ≤ 10000s) and temperature coefficient of 5×10
^-14
/°C are measured. Engineering modification and environmental test are carried out.